Antiaromatic Carbaporphyrinoids: Fluorene as a Fused Motif toward the Synthesis of <i>meso</i>-Fused Heterobenziporphyrins

Kumar, Ankit; Laxman, Kandala; Ravikanth, Mangalampalli

doi:10.1021/acs.orglett.9b03329

Cited by 27 publications

(42 citation statements)

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“…Ravikanth and co-workers synthesized antiaromatic carbaporphyrins, meso-fused heterobenziporphyrins 27 a-c using fluorene as a fused motif embedded in the macrocycle as shown in Scheme 5. [23] The precursor, 2-benzoylfluorene 28 a was synthesized by treating fluorene with benzoyl chloride under Friedel-Crafts conditions which was then oxidized by KMnO 4 in pyridine to give 2-benzoyl-9-fluorenone 29. The fluorenone 29 was reduced with NaBH 4 in THF/CH 3 OH to obtain 9-hydroxy-2-(phenylhydroxymethyl)fluorene 30.…”

Section: (Ii) Pahs Embedded Porphyrins With Three Meso Carbons (Fusedmentioning

confidence: 99%

Polycyclic Aromatic Hydrocarbon‐/Heterocycle‐Embedded Porphyrinoids

2020

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Porphyrinoids in which one or two pyrrole rings are replaced with polycyclic aromatic hydrocarbons/heterocycles such as naphthalene, phenanthrene, biphenyl, bipyridine, or phenanthroline are a new class of porphyrinoids represented as polycyclic aromatic hydrocarbon (PAH)‐/heterocycle‐embedded porphyrinoids. These macrocycles possess the structural features of both polycyclic aromatic hydrocarbons/heterocycles and cyclic polypyrrolic porphyrinoids. The PAH‐embedded porphyrinoids have drawn significant interest in recent times because of the following: (1) these macrocycles exhibit different π‐conjugation pathways unlike porphyrinoids, which exhibit circular conjugation pathways in their macrocyclic rings with various molecular structures; (2) the PAHs embedded macrocycles show variable degree of aromaticity which varies from weak aromaticity to antiaromaticity and (3) the PAHs embedded porphyrinoids provide unique ligand environment to form stable coordination and organometallic complexes in which metals may show uncommon oxidation states and unusual reactivity. All these above‐listed features depend on polycyclic aromatic hydrocarbon/heterocycle moiety present as a part of porphyrinoid macrocyclic framework. This Minireview focuses on the synthesis of different polycyclic aromatic hydrocarbon‐/heterocycle‐embedded porphyrins, contracted porphyrins and expanded porphyrins and briefly discusses their structural, spectral, aromatic and coordination properties.

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Section: (Ii) Pahs Embedded Porphyrins With Three Meso Carbons (Fusedmentioning

confidence: 99%

Polycyclic Aromatic Hydrocarbon‐/Heterocycle‐Embedded Porphyrinoids

2020

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“…In a similar way, meso -fused heterabenziporphyrins 371.5a – c and their palladium complexes 371.6a , b were obtained by the same group. 717 These systems showed weak absorptions in the NIR range, with a progressive red-shift observed in analogues containing heavier chalcogen heteroatoms. Related designs from the Ravikanth group include the strained fluorenophyrins 371.7a , b , 718 dibenzofuran/dibenzothiophene-based macrocycles 371.8a – c , 719 and their contracted benzofuran/benzothiophene analogues 371.9a , b .…”

Section: Macrocyclic Systemsmentioning

confidence: 99%

“… Reagents and conditions: (a) 716 (1) BF 3 ·OEt 2 , C 6 F 5 CHO, (2) DDQ; (b) 716 PCl 3 , TEA, toluene, reflux, 1 h; (c) 717 PdCl 2 , CHCl 3 /CH 3 CN, reflux. …”

Section: Macrocyclic Systemsmentioning

confidence: 99%

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

et al. 2021

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“…This supporting information is available on the ACS Publication Website free of charge. Characterization data like HRMS, 1 H, 13 C, 2D NMR, absorption and electrochemical data and DFT studies of all the compounds that is reported are present in the supporting information.…”

Section: Associated Content Supporting Informationmentioning

confidence: 99%

Synthesis of Stable Nonaromatic Fluorenonephyrin Macrocycle

et al. 2021

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A new derivative of our recently reported nonaromatic fluorenophyrin 5 named fluorenonephyrin 6 was synthesized over a sequence of six steps starting with commercially available fluorene as precursor. Our attempts to direct oxidation of 5 to 6 were not successful. Hence, we synthesized 2,7-bis(phenyl(1H-pyrrol-2-yl)methyl)-9-fluorenone (fluorenone tripyrrane) in five simple steps from fluorene, and condensed it with pentafluorobenzaldehyde under mild acidic conditions in CH 2 Cl 2 followed by oxidation with DDQ and chromatographic purification to afford fluorenonephyrin (9%). 6 was characterized and studied by HR-MS, 1D and 2D NMR spectroscopy, absorption, electrochemical and DFT/TD-DFT techniques. The DFT studies revealed that 6 was more distorted than 5 and that introduction of C=O in the macrocyclic core remarkably distorts the pyrrole rings of the dipyrrin unit from the mean plane of macrocyclic framework. The macrocycle showed a band at around 390 nm and a broad band at around 650 nm. The redox properties indicated that the macrocycle was highly electron-deficient in nature. TD-DFT studies were in accordance with the experimental observations.

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Antiaromatic Carbaporphyrinoids: Fluorene as a Fused Motif toward the Synthesis of meso-Fused Heterobenziporphyrins

Cited by 27 publications

References 27 publications

Polycyclic Aromatic Hydrocarbon‐/Heterocycle‐Embedded Porphyrinoids

Polycyclic Aromatic Hydrocarbon‐/Heterocycle‐Embedded Porphyrinoids

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

Synthesis of Stable Nonaromatic Fluorenonephyrin Macrocycle

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